Photographic flashlamp unit

ABSTRACT

A multilamp photographic flash unit, the lamps of which are of the percussive primer type, having self-contained elements in the form of a folded torsion spring for firing the lamps. The folded torsion spring is formed in the shape of a hairpin having first and second segments joined by a light. One of the segments has a striker member thereon for firing the lamps. The spring is cocked by crossing the segments over one another and thereafter restraining the striker in the biased condition.

United States Patent [72] Inventor Thomas B. McDonough Allenwood, Pl. 121 1 Appl. No. 785,097 22 Filed Dec. 19,1968 I45] Patented Aug. 3, 1971 [73] Assignee Sylvanin Electric Products Inc.

[54] PHOTOGRAPHIC FLASHLAMPUNIT 4 Claims, 3 Drawing Figs.

[52] U.S.Cl.-. 240/13, 431/93 51 1 Int. Cl. G03b 15/02 [50] fieldolSearch 240/13; 95/] 1, 11.5; 43 1/92, 93, 94, 95

[56] References Cited UNITED STATES PATENTS 3,508,478 4/1970 Brooks 95/1 1 FOREIGN PATENTS 350,887 4/1905 France 431/92 635,443 9/1936 Germany...v 431/93 1,1 92,047 4/1965 Germany.... 431/95 Primary Examiner-Samuel S. Matthews Assistant ExaminerF red Lv Braun Attorneys-Norman J. OMalley and Joseph C. Ryan ABSTRACT: A multilamp photographic flash unit, the lamps of which are of the percussive primer type, having self-contained elements in the form of a folded torsion spring for firing the lamps. The folded torsion spring is formed in the shape of a hairpin having first and second segments joined by a light. One of the segments has a striker member thereon for firing the lamps. The spring is cocked by crossing the segments over one another and thereafter restraining the striker in the biased condition.

PATENTED Am: 3 I971 FIG-2 THOMAS B. McDONOUGH INVENT WW .ATTORNE PHOTOGRAPI-IIC FLASI-ILAMP UNIT This invention relates to multilamp photographic flash units, commonly called flashcubes, and more particularly to flashcubes having lamps of the percussive primer type and the elements employed to fire them.

Generally speaking, a percussive-type photoflash lamp comprises an hermetically sealed, light-transmitting envelope containing a source of actinic light and having a primer secured thereto. More particularly, the percussive-type photoflash lamp may comprise a length of glass tubing constricted to a tip at one end thereof and having a primer sealed therein at the other end thereof. The length of glass tubing which defines the lamp envelope contains a combustible such as shredded zirconium foil and a combustion-supporting gas such as oxygen. The primer may comprise a metal tube and a charge of fulminating material on a wire anvil supported therein. Operation of the lamp is initiated by an impact onto the tube of the primer to cause deflagration of the fulminating material on the wire anvil up through the tube to ignite the combustible disposed in the lamp envelope.

Heretofore it has been suggested that impacting of the primer tube to cause deflagration of the fulminating material disposed therein be accomplished by means of some form of striker mechanism built into the camera with which the lamp would be used. However, because of several, substantial, practical disadvantages which characterize this approach, more recently it has been suggested that the striker mechanism be integrated into the flashcube itself. More particularly, it has been suggested that the striker mechanism be in the form of a torsion spring, with each lamp in the flashcube having its own torsion spring striker mechanism associated therewith. The particular type of striker mechanism with which this invention is concerned is a folded torsion spring with the stationary end thereof shaped to function as a latch to hold the striker formed on the movable end thereof while the spring is in a cocked position.

In view of the foregoing, the principal object of this invention is to provide an improved form of folded torsion spring as the striker mechanism to provide the impact necessary to cause deflagration of the fulminating material disposed in the primer tube of a percussive-type photoflash lamp up through the tube to ignite the combustible comprising the source of actinic light disposed in the lamp envelope.

Another object is to provide a folded torsion spring which has a definite striker movement and which delivers high velocity and efficient energy transfer to the primer tube of a percussive-type flashlamp.

A further object is to provide a folded torsion spring having a configuration such that the striker thereof will not become uncocked accidentally due to mechanical shock or vibration.

These and other objects, advantages and features of this invention are attained, in accordance with the principles of this invention, by shaping the folded torsion spring into a configuration somewhat like a hairpin and wherein the lower portion of the segment, of which the striker comprises an extension, lies behind the other segment, of which the stationary arm comprises an extension. This configuration prevents inadvertent uncocking and provides a well-defined striker movement resulting. in high striker velocity and efficient energy transfer to the percussive flashlamp system.

In the specific embodiment of the invention illustrated in the accompanying drawing, FIG. 1 is a perspective view of a flashcube embodying the principles of this invention with a portion of the flashcube broken away for clarity of illustration.

FIG. 2 is a fragmentary view on an enlarged scale of a single lamp-firingspring assembly.

FIG. 3 is a plan view of the base of the flashcube of FIG. 1 with the several spring members shown in full and the several flashlamps associated therewith shown in phantom.

In the specific embodiment illustrated in the accompanying drawing, the flashcube 2 comprises a substantially rectangular base 4 along each side of which a percussive-type flashlamp 6 is arranged. Each lamp 6 is provided with its own reflector 8 and the assemblage of the lamps and reflectors is enclosed in a transparent container 10 secured to the base 4. Each lamp 6 comprises an hermetically sealed light-transmitting envelope 12 having a primer depending therefrom and filling of com bustible foil 14 and a combustion-supporting gas disposed therein. The primer comprises a metal tube 16 within which an anvil and a charge of fulminating material are disposed.

As shown particularly in FIG. 2, the folded torsion spring 1 was fonned from 0.026 inch diameter music wire about 2.75 inches long. The wire is shaped to define a hairpin torsional section having segments 3 and 5 and a bight 7. The end portion of segment 3 is shaped to define a stationary supporting leg 9, the tip of which is shaped to define a catch 11. The end portion of segment 5 is shaped to define a striker 13 which, when the spring is cocked as shown, crosses over the supporting leg 9 and is restrained by catch 11. The stationary supporting leg 9 is seated in an elongated slot formed in the base 4 on or near a diagonal thereof, said slot being sufficiently shallow so that the catch 11 formed on the free end of the leg 9 will project a relatively substantial distance above the plane of the top face of the base 4. The center post 15 on the top face of the base 4 provides a suitable bearing surface for the heel of the striker during cocking and it also aids in preventing accidental displacement of the spring 1 sufficient'to free the striker from the catch sometime after cocking and before fir ing is intended.

In accordance with the principles of this invention, the lower portion of segment 5 of the hairpin torsional section of the folded torsion spring 1 lies behind segment 3 thereof, thus preventing the heel of the striker 13 from moving toward the catch 11. This arrangement prevents inadvertent uncocking from shock and provides a pivot which defines the striker travel. Displacement of the cocked striker 13, to release it from the catch 11 and thus permit it to strike the tube 16 of the primer and fire the lamp, is effected by a suitable finger 18 or the like moving up through a slot 20 provided therefor in the base. The finger 18 may be part of a camera mechanism designed to enable the photographer to flash the lamp in synchronization with the tripping of the camera shutter to take a picture. Thus when the finger l8 pushes the striker 13 upwardly a distance sufficient to clear the top of the catch 11, the striker swings clockwise as shown by the arrow in FIG. 2 and hits and indents the impact-sensitive primer tube 16 at high velocity to cause deflagration of the fulminating material located therein and thus ignite the combustible foil 14.

The bottom face of the base 4 of the flashcube 2 is provided with a suitable center post or the like (not shown) for mounting on a camera and providing a means whereby the flashcube may be rotated after a lamp has been flashed so that another lamp may be advanced to firing position. As illustrated in FIGS. 1 and 3, each of the four flashlamps 6 is provided with its own firing mechanism as shown in detail in FIG. 2 and described above. As shown in FIG. 1, the hairpin torsional sections of the springs are clustered in the space behind the reflectors 8 and sufiicient clearance is provided along the lower edges of these reflectors to permit the strikers to operate freely.

What I claim is:

l. A photographic flashlamp unit comprising:

a platform;

a plurality of flashlamps mounted on said platform, each of said flashlamps comprising an hermetically sealed, lighttransmitting envelope having a source of actinic light disposed therein and a primer depending therefrom;

and a folded torsional spring mounted on said platform for firing said primer and thus effecting ignition of said source of actinic light, said spring comprising a substantially hairpin torsional section having a first segment and a second segment joined by a bight, a striker projecting from one of said segments and a supporting leg projecting from the other of formed at the tip thereof, said segments crossing one said segments said leg having a catch therewith.

4. The combination of claim 1 and a plurality of reflectors located on said platform, one for each of said flashlamps, said reflectors being arranged so that the rear faces thereof define a central chamber, said folded torsional spring being located primarily within said central chamber. 

1. A photographic flashlamp unit comprising: a platform; a plurality of flashlamps mounted on said platform, each of said flashlamps comprising an hermetically sealed, lighttransmitting envelope having a source of actinic light disposed therein and a primer depending therefrom; and a folded torsional spring mounted on said platform for firing said primer and thus effecting ignition of said source of actinic light, said spring comprising a substantially hairpin torsional section having a first segment and a second segment joined by a bight, a striker projecting from one of said segments and a supporting leg projecting from the other of said segments said leg having a catch formed at the tip thereof, said segments crossing one another and said striker crossing said leg with said catch restraining said striker in a cocked condition.
 2. The combination of claim 1 in which said platform includes access means for enabling said cocked striker to be tripped.
 3. The combination of claim 1 in which each of said flashlamps has its own folded torsional spring associated therewith.
 4. The combination of claim 1 and a plurality of reflectors located on said platform, one for each of said flashlamps, said reflectors being arranged so that the rear faces thereof define a central chamber, said folded torsional spring being located primarily within said central chamber. 